After his last campaign event of the night Sunday, Perry was approached by a teenaged girl who questioned him about his recent Iowa ad taking aim at gays serving openly in the military.

"I'm just wondering why you're so opposed to gays serving openly in the military and you want to deny their freedom when they're fighting and dying for your right to run for president?" asked 14-year-old Rebecka Green, who was accompanied to the Decorah town hall by her father Todd.

Perry, who has faced scattered protests on the issue throughout his bus tour in Iowa, told the young woman that he believed President Barack Obama was pressured to change a functional "Don't Ask Don't Tell" policy by a progressive voting block.

"Don't Ask Don't Tell was working," he said, later adding "This president was forced by his base to change that policy."

Perry said that a voter recently asked him how he would feel if his son or daughter was gay. "I'd feel the same way," he said, recounting his answer. "I'd hate the sin but I'd love the sinner."

Green told reporters after the exchange that she wasn't satisfied by Perry's answer. "Nobody should be able to tell anybody who they can or cannot love," she said. Her father, a Democrat who teaches religion at a nearby college, said that he brought her to the event because she was outraged by the premise of the ad.

The exchange wasn't the only tense moment of the evening at an otherwise subdued town hall.

Asked about the dangers of hydraulic fracking, Perry launched into his common claim that there is no documentation of groundwater contamination as a result of the practice, which he says is safely conducted in Texas.